diff --git a/src/app/features/settings/about/About.tsx b/src/app/features/settings/about/About.tsx
index 082317d37..f3535d83e 100644
--- a/src/app/features/settings/about/About.tsx
+++ b/src/app/features/settings/about/About.tsx
@@ -8,6 +8,7 @@ import { getOriginBaseUrl, withOriginBaseUrl } from '../../../pages/pathUtils';
 import pkg from '../../../../../package.json';
 import { clearCacheAndReload } from '../../../../client/initMatrix';
 import { useMatrixClient } from '../../../hooks/useMatrixClient';
+import { tauriInvoke } from '../../../hooks/useTauri';
 
 const LotusLogo = withOriginBaseUrl(getOriginBaseUrl(), '/public/res/lotus-logo.png');
 
@@ -78,6 +79,51 @@ function useServerSupport(): { support: MSC1929Support | null; loading: boolean
 type AboutProps = {
   requestClose: () => void;
 };
+/**
+ * [Gitea #276] Which build someone is on: the web deploy's commit and build
+ * date (stamped in by vite.config.js), plus the desktop app's own version from
+ * Tauri, the number a desktop or updater bug report needs.
+ */
+function BuildInfo() {
+  const [desktopVersion, setDesktopVersion] = useState<string>();
+  useEffect(() => {
+    tauriInvoke()?.('plugin:app|version')
+      .then((v) => {
+        if (typeof v === 'string') setDesktopVersion(v);
+      })
+      .catch(() => undefined);
+  }, []);
+  const commit = __LOTUS_BUILD_COMMIT__;
+  const built = new Date(__LOTUS_BUILD_DATE__);
+  const builtText = Number.isNaN(built.getTime())
+    ? undefined
+    : built.toLocaleString(undefined, { dateStyle: 'medium', timeStyle: 'short' });
+  return (
+    <Box direction="Column" gap="0">
+      {desktopVersion && (
+        <Text size="T200" priority="300">
+          Desktop {desktopVersion}
+        </Text>
+      )}
+      <Text size="T200" priority="300">
+        Web build{' '}
+        {commit !== 'unknown' ? (
+          <a
+            href={`https://code.lotusguild.org/LotusGuild/cinny/commit/${commit}`}
+            target="_blank"
+            rel="noreferrer noopener"
+          >
+            {commit}
+          </a>
+        ) : (
+          commit
+        )}
+        {builtText && ` · built ${builtText}`}
+      </Text>
+    </Box>
+  );
+}
+
 export function About({ requestClose }: AboutProps) {
   const mx = useMatrixClient();
   const { support: serverSupport, loading: supportLoading } = useServerSupport();
@@ -117,6 +163,7 @@ export function About({ requestClose }: AboutProps) {
                       <Text size="T200">v{pkg.version}</Text>
                     </Box>
                     <Text>A Matrix client for Lotus Guild.</Text>
+                    <BuildInfo />
                   </Box>
 
                   <Box gap="200" wrap="Wrap">
diff --git a/src/ext.d.ts b/src/ext.d.ts
index 844a21747..6db433e1d 100644
--- a/src/ext.d.ts
+++ b/src/ext.d.ts
@@ -1,5 +1,9 @@
 /// <reference types="vite/client" />
 
+// [Gitea #276] Set by vite.config.js `define`.
+declare const __LOTUS_BUILD_COMMIT__: string;
+declare const __LOTUS_BUILD_DATE__: string;
+
 declare module 'browser-encrypt-attachment' {
   export interface EncryptedAttachmentInfo {
     v: string;
diff --git a/vite.config.js b/vite.config.js
index 1aaf5c5f6..739304f0e 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -6,6 +6,7 @@ import { viteStaticCopy } from 'vite-plugin-static-copy';
 import { vanillaExtractPlugin } from '@vanilla-extract/vite-plugin';
 import { VitePWA } from 'vite-plugin-pwa';
 import fs from 'fs';
+import { execSync } from 'child_process';
 import path from 'path';
 import buildConfig from './build.config';
 
@@ -272,8 +273,26 @@ const vendorChunks = (id) => {
   if (id.includes('node_modules/chroma-js')) return 'chroma';
 };
 
+// [Gitea #276] Which build is this? The short commit and build time are shown
+// in Settings → About (web deploys change many times a day while the package
+// version stays the same). LOTUS_BUILD_COMMIT overrides; no git → "unknown".
+const buildCommit = (() => {
+  if (process.env.LOTUS_BUILD_COMMIT) return process.env.LOTUS_BUILD_COMMIT.slice(0, 12);
+  try {
+    return execSync('git rev-parse --short=8 HEAD', { stdio: ['ignore', 'pipe', 'ignore'] })
+      .toString()
+      .trim();
+  } catch {
+    return 'unknown';
+  }
+})();
+
 export default defineConfig({
   appType: 'spa',
+  define: {
+    __LOTUS_BUILD_COMMIT__: JSON.stringify(buildCommit),
+    __LOTUS_BUILD_DATE__: JSON.stringify(new Date().toISOString()),
+  },
   publicDir: false,
   base: buildConfig.base,
   server: {